Thanks for the quick response. Here are the project and source files, which were all exported out of Premiere cc2019. The project is currently set to a color depth of 32 bits/channel and what you'll see is that the ProRes and PreRes(HQ) files are darker than the the other two files. Change the project color depth to 8 or 16 bit and they all look alike. This is all within After Effects, although the images retain the problem when exported.

I managed to get "Blackmagic Playback" to stick as the Audio Device by setting it, leaving Preferences, (at which point the sequence won't play), then opening a different sequence. This all then works as it should until you leave the project. When you come back in it often reverts back to "Adobe Desktop Audio". Sometimes it works, but not for long. You notice the A/V sync has gone out and when tested the audio is some 7 frames behind the picture. Checking in Preferences once again "Adobe Desktop Audio" has magically been selected.

Preferences/Playback/Audio Device:
Select something other than "Adobe Desktop Audio", such as Blackmagic Playback, and hit OK to leave settings. Playback via Blackmagic then doesn't work and returning to Preferences has "Adobe Desktop Audio" selected again. This means that you can't use 'offsets' in the same panel to make your monitoring in sync.

Tested with several Blackmagic drivers - always the same result.
Re-tested with cc2019 and everything works fine.

Had this error a lot when trying to export today. It often happens when exporting ProRes (HQ) but not when exporting ProRes. When the error came up the resultant files had issues such as frames in the wrong order.
Premiere 13.1.2
OSX: 10.14.5

Currently, Premiere uses the Lanczos method for intrinsic scale and rotation. Lanczos is an exceptionally high-quality interpolation method which generally yields better results than bicubic, bilinear or nearest neighbor. From reading the forum post, it seems that up-scaling is the real issue here. I suggest looking at the Detail-Preserving Upscale effect in After Effects. It does a really good job and gives you some parameters to tweak to fit your specific content.

This is also happening with ProRes 4444 files. A very similar problem has been found with After Effects cc2019. Sequence settings options seem to affect things. Checking "composite in linear color" can change things. As can deselecting "maximum bit depth"

Another reason to keep the Legacy Title tool - we have some custom software that generates large numbers of caption .prtl files from a text document. These can then be imported into Premiere and laid into place. This workflow saves us hours of manually copy/pasting on-screen text. We have tried to implement the workflow by generating XML files containing Essential Graphic titles, but the formatting of the Essential Graphics within an XML is not intuitive. If someone can explain how Essential Graphics are formatted within XMLs then we'd have less need for the Legacy Title Tool, but right now it's essential for our workflow.

while this is a rather critical and large change to the way the application works and will take some time to be implemented, we’ll definitely put this under consideration.

There’s more than one solution to this problem, though.

A good short term opportunity is to use the parallel install feature in the creative cloud application. It should help to at least take away some of the issues working with people on a different version of the application.

Another thing worth keeping in mind is that you can install CC on two different machines (if you’re on an individual subscription). That gives you additional opportunity to keep different versions around for compatibility reasons.